With continuous developments of liquid crystal display technology, liquid crystal modules (LCMs) have been widely used in electronic terminals such as mobile phones and tablet computers. However, as the liquid crystal display panel of a liquid crystal module does not have a light emitting function, a backlight is required to be disposed under the liquid crystal display panel to provide the light source that it needs, so as to achieve display effects.
As shown in FIG. 1, which is a schematic structural diagram of an existing liquid crystal module, the liquid crystal module comprises: a back plate 11, a bottom reflective film 12, a backlight 13, an optical sheet(s) 14, a liquid crystal display panel 15, etc. The backlight 13 is used to provide the light required by the liquid crystal display panel 15, so that the liquid crystal display panel 15 achieves display effects.
Specifically, as shown in FIG. 2, which is a schematic structural diagram of an exemplary existing backlight 13, the backlight 13 comprises: a light guide plate (LGP) 131, an LGP fixing element 132 for fixing the LGP 131, and at least one light source 133 disposed at a side of the LGP 131. The LGP 131 is used to, based on light diffusion principle, convert the light emitted from the light source 133 into planar light, which, after regulated by the optical sheet 14 in the liquid crystal module, such as diffused, deflected, converged and adjusted in angle, exits the liquid crystal display panel 15 in the liquid crystal module; the LGP fixing element 132 is used to implement fixture of the LGP 131, and to avoid the shake of the LGP 131 during the testing of the liquid crystal module and the problem of scratching the optical sheet 14 in the liquid crystal module due to the friction between the LGP 131 and the optical sheet 14 and thus affecting image quality of the liquid crystal display panel 15.
However, as the existing LGP 131 and the existing LGP fixing element 132 are usually made of thermal-expansive materials which expand with heat, such as polymethyl methacrylate (PMMA) or polycarbonate (PC), the LGP 131 and the LGP fixing element 132 both expand with heat during a test at a high temperature and a high humidity (refer to the schematic diagram of the backlight in a state of thermal expanding as shown in FIG. 3). Thus, at normal temperatures, when the LGP fixing element 132 is used to fix the LGP 131, a certain gap (usually about 0.3˜1.2 mm) is usually preset between the LGP 131 and the LGP fixing element 132, so that the LGP 131 can freely expand and contract without resistance when it expands with heat. However, if the preset gap is too big, problems such as the shake of the LGP 131 will be easily incurred during a reliability test of the liquid crystal module, and the phenomenon of scratching the optical sheet 14 due to the friction between the LGP 131 and the optical sheet 14 and thus the lowering of the image quality of the liquid crystal display panel 15 will occur. If the preset gap is too small, then when the performance test of the liquid crystal module is conducted in an environment of high temperature and high humidity, the LGP 131 and the LGP fixing element 132 both expand with heat, and thus they block each other so that the LGP 131 becomes warped, abutting against the surface of the optical sheet 14, thereby affecting the image quality of the liquid crystal display panel 15.